Native to the West Indies and Mexico, Yellow Alder is a perennial, dense, compact shrub that reaches 2½ feet in height. Dark green leaves are clustered toward the tips of the branches, lanceolate to oblong-lanceolate or narrowly elliptic, 4-13 X 2-3 cm, margins doubly serrate.

Turnera ulmifolia occurs on all island groups in the Bahamian Archipelago as well as Florida, the entire Caribbean region, India, Srilanka, and almost all tropical and subtropical regions throughout the entire world.

The 5 cadmium yellow petals of the buttercups wide face, but form a funnel for the center with filaments in a matching yellow color. The flowers close up at night and open when the sun hits them. This opening and closing gave them several nicknames of Bankers Bush and Politicians Flower because the flowers open at 10 and close by 2. Flowers turn to tiny insignificant fruits, which turn to seed and will re-seed on their own. The actinomorphic flowers are arranged solitarily in leaf axils. The flowers are subtended by 3 bracts. The calyx has 5 fused green sepals. The corolla has 5 unfused yellow petals. There are 5 stamens, each fused to the base of a petal. The ovary is superior with a single locule and many seeds. The fruit is a capsule at maturity. Flowers are bright yellow buttercups, which look great against the dark-green foliage. The blowers might be slightly brownish towards the center. It can become tall and leggy if not pruned. In the landscape it performs well in mass plantings, as a border or as a groundcover. It also works well in butterfly gardens. Yellow alder is propagated by seed, cuttings or division.

Turnera Ulmifolia – Yellow Alder – Ajaytao

One detects a slight aromatic fragrance, and see butterflies and pollinators all around. It is a must have plant for any butterfly garden. Bees and Butterflies love-love-love any nectar from its tasty little flowers. One enjoy’s watching Honey bees, Long tailed Skippers, White Peacocks and Sulphur butterflies hovering, basking and sipping on one flower to the next.

Many stems originate close to the ground but they branch infrequently forming an open, leggy plant. Those in the full sun branch more and stay fuller than those in partial shade. Clear yellow flowers are produced daily, each lasting several hours before closing at night. New flowers open the next morning. Leaves stay dark green with little or no fertilizer.

Blooming Time: Blooms sporadically all year long; The yellow blooms are 2½ inches across and last only one day.

Culture: Turnera ulmifolia do best in a well-drained potting mix (1 part peat moss to 2 parts loam to 1 part sand or perlite). They like intermediate temperatures of 60 to 85 degrees, but can take higher day time temperatures if shaded from hot afternoon sun. In the greenhouse, we grow them under 25% shade all year long. The plants need a fair amount of water to keep from wilting on hot days. Fertilize weekly with a balanced fertilizer diluted to ½ the strength recommended on the label. During winter months, water should be restricted and fertilizer applications should be once a month. The leaves of this plant have a pungent odor when crushed that some people find offensive.

Propagation: Turnera ulmifolia is propagated by seed, cuttings, or by division. It is best to start seed in spring. Cuttings can be rooted any time of the year, roots easily in water or moist sand. Divisions should be taken in spring when new growth emerges.

Space plants several feet apart to form a ground cover in one season. To thicken the plant, cut stems back when they become leggy to force new branches close to the ground. To use as a low maintenance plant, consider locating alder alone as an accent in a shrub border or in a ground cover to display its natural open habit. It will display its bright yellow flowers on the outside edge of the plant without pruning. Alder seedlings often germinate near the plants and can become weeds in the landscape.

Plant yellow alder in the full sun or partial shade for best form and flowering. Plants appear to adapt to a variety of soil conditions including alkaline pH and dry sites. Freezing temperatures kill plants to the ground, but warm spring weather brings them back to life in central and south Florida.

Turnera Ulmifolia – Yellow Alder – Ajaytao

Pests and Diseases

White flies are often found on the foliage. Severe infestations can injure the plants. Aphids and scales can also infest the foliage, but they are usually not too serious. A recent study found that yellow alder potentiated the antibiotic activity against methicillin—resistant Staphylococcus aureus.

New laboratory evidence suggests that yellow alder (Turnera ulmifolia) extract may enhance the effects of antibiotics in the treatment of methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a type of bacteria that does not respond to treatment with certain antibiotics, including ampicillin (Principen®) and other penicillins.

Researchers tested the effects of an extract made from the Brazilian herb yellow alder, alone and in combination with antibiotics, against MRSA. They found that the herb alone did not have significant antimicrobial activity. However, when combined with other antibiotics (kanamycin and gentamicin), the anti-MRSA effects were significantly improved.

“Extracts from Turnera ulmifolia could be used as a source of plant-derived natural products with resistance-modifying activity, constituting a new weapon against the problem of bacterial resistance to antibiotics demonstrated in MRSA strains,” The authors concluded in the journal BMC Complementary and Alternative Medicine.

Although these early results are promising, additional research in humans is needed to determine if this is a safe and effective therapy.

Traditionally, yellow alder has been used an anti-inflammatory and expectorant, although human evidence is limited.

Preliminary lab studies published earlier this year suggest that compounds in marijuana and honey may also have antibacterial effects against MRSA infections. However, more research is needed in humans before conclusions can be made.

MRSA is a serious medical condition that requires medical treatment. Integrative therapies should not replace or delay treatment with more proven techniques or therapies.Ajaytao Photography